Japanese Unexamined Patent Application Publication No. 2009-198054 discloses a gas turbine combustor 1 provided with a combustion cylinder 2, a premixing tube 3, and a fuel supply unit 5. The gas turbine combustor 1 is configured to allow the fuel supply unit to supply the fuel to an annular fuel passage 16 along a tangential direction so that the fuel is uniformly injected through an annular nozzle portion 19. The injected fuel is atomized by air from a circumferential air passage 22 that surrounds the nozzle portion, and an axial flow is generated in the combustor. Meanwhile, air flowing inside through holes 25 in a peripheral wall surface of the premixing tube generates a swirl flow that surrounds the axial flow within the combustor. As a result, the flame is retained at a position apart from a top portion of the combustion cylinder so that a heat shield plate 6 is not excessively heated, resulting in improved durability. The resultant gas turbine combustor has durability higher than that of generally employed type, and improved emission characteristics.
However, the aforementioned generally employed gas turbine combustor has a difficulty in stabilization of the flame resulting from the swirl flow supplied inside through the holes formed in the peripheral wall surface of the premixing tube, which intrudes the premixing tube toward the center to disturb uniformity of the axial flow at the center part of the premixing tube.
The nozzle employed in the generally employed gas turbine combustor also has a problem of insufficient shear force to atomize the liquid film of the air blasted fuel fed from the filmer because the straight air flow only exists around the fuel liquid film.